/*
 * (c) Copyright 2007, 2008, 2009 Hewlett-Packard Development Company, LP
 * All rights reserved.
 * [See end of file]
 */

package com.hp.hpl.jena.sparql.expr;

import com.hp.hpl.jena.graph.Node ;
import com.hp.hpl.jena.sparql.ARQInternalErrorException ;
import com.hp.hpl.jena.sparql.core.Var ;
import com.hp.hpl.jena.sparql.engine.Renamer ;
import com.hp.hpl.jena.sparql.engine.binding.Binding ;
import com.hp.hpl.jena.sparql.expr.aggregate.Aggregator ;
import com.hp.hpl.jena.sparql.util.Utils ;

/**
 * Group aggregation functions calculate a value during grouping and place it in the output binding.  This class is relationship of  an aggregation expression and that variable.  Evaluation returns the variable's bound value.
 */

public class E_Aggregator extends ExprVar
{
    /**
	 * @uml.property  name="aggregator"
	 * @uml.associationEnd  
	 */
    protected Aggregator aggregator ;
    
    public E_Aggregator(String name, Aggregator agg)    { super(name) ; aggregator = agg ; }
    public E_Aggregator(Node n, Aggregator agg)         { super(n) ; aggregator = agg ; }
    public E_Aggregator(Var v, Aggregator agg)          { super(v) ; aggregator = agg ; }
    
    public void setVar(Var var)
    { 
        if ( super.varNode != null )
            throw new ARQInternalErrorException(Utils.className(this)+": Attempt to set variable to "+var+" when already set as "+super.varNode) ;
        super.varNode = var ;
    }
    
    /**
	 * @return
	 * @uml.property  name="aggregator"
	 */
    public Aggregator getAggregator()   { return aggregator ; }
    
    @Override
    public int hashCode() { return super.hashCode() ; }
    
    @Override
    public boolean equals(Object other)
    {
        if ( this == other ) return true ;
        if ( ! super.equals(other) ) return false ;
        if ( ! ( other instanceof E_Aggregator ) )
            return false ;
        E_Aggregator agg = (E_Aggregator)other ;
        return aggregator.equalsAsExpr(agg.aggregator) ;
    }

    // As an expression suitable for outputting the calculation. 
    @Override
    public String asSparqlExpr()        
    { return aggregator.toString() ; }
    
    @Override
    public E_Aggregator copySubstitute(Binding binding, boolean foldConstants, Renamer renamer)
    {
        Var v = varNode ;
        Aggregator agg = aggregator ;
        if ( renamer != null )
        {
            v = (Var)renamer.rename(varNode) ;
            agg = aggregator.copyRename(renamer) ;
        }
        return new E_Aggregator(v, agg) ;
    }
    
    // DEBUGGING
    @Override
    public String toString()
    // Don't call super.toString - that will call asSparqlExpr()!
    // varNode can be null temporarily as a structure is built.
    { return "(AGG "+
                (varNode==null?"<>":"?"+super.varNode.getVarName())+
                " "+aggregator.toString()+")"; }
    
    @Override
    public Expr copy()  { return new E_Aggregator(varNode, aggregator.copy()) ; }
}

/*
 * (c) Copyright 2007, 2008, 2009 Hewlett-Packard Development Company, LP
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */